1. Field of the Invention
The present invention relates to the field of video game systems and networked computer systems.
2. Description of Related Art
Home video game machines such as the "SEGA GENESIS.TM." and the "SUPER NINTENDO ENTERTAINMENT SYSTEM.TM." are designed to function primarily as computing, graphics, and sound engines for video game software provided on insertable ROM-based cartridges. "SEGA.TM." and "SEGA GENESIS.TM." are trademarks of "SEGA, INC..TM." "SUPER NINTENDO ENTERTAINMENT SYSTEM.TM." and "NINTENDO.TM." are trademarks of Nintendo, Inc. Such video game software is created by "SEGA.TM." and "NINTENDO.TM." as well as various third-party software vendors and is available at retail outlets throughout the world. Such ROM-based cartridge games are written to be played by 1, 2, or possibly 4 or more players at once, with each player utilizing a controller attached to the video game machine.
Because such games are ROM-based, once the software is frozen into a ROM, it cannot be modified substantially in the field. Thus, once a cartridge is manufactured and sold to the customer, the execution of the game is essentially locked-in. If the customer, manufacturer, or another party desires to substantially enhance the functionality of an existing video game cartridge, it is necessary to redesign the software and manufacture and distribute the modified cartridge with a new ROM. Clearly, this is an extremely expensive solution, and it would be desirable to provide a convenient and cost-effective means by which video game software could be enhanced in the field.
In the past few years video game enhancement devices have appeared that allow minor modification to the execution of video game cartridges in the field. A well-known such device is the "GAME GENIE.TM.", by "GALOOB.TM.". "GAME GENIE.TM." and "GALOOB.TM." are trademarks of "GALOOB INC..TM." The Game Genie (and like devices) plugs into a video game console's cartridge slot, and then the video game cartridge which the user desires to enhance is plugged into a cartridge connector on top of the "GAME GENIE.TM.". When power is applied to the video game console, the "GAME GENIE.TM." intercepts the video game's processor accesses intended for the ROM cartridge, and directs the processor to execute out of a "GAME GENIE.TM." ROM. This ROM contains a small amount of software that puts up a graphics image and requests the user to enter special codes with a video game controller. The user, referring to a printed list of special codes either provided by the manufacturer or some other source (e.g. a video game magazine), then enters the codes for the desired enhancement of the game. These special codes specify memory addresses and data values. Once the codes are entered, the "GAME GENIE.TM." will turn over control to the game cartridge, and normal game execution will begin. However, when the processor attempts to fetch data from one of the addresses which had been entered as a code, the "GAME GENIE.TM." will intercept the transaction (it has an address comparator for each address it intercepts) and substitute the entered data value instead. Because the "GAME GENIE.TM." can only substitute the values of a small number of individual data words, the achievable modifications to video game cartridges are fairly slight, such as increasing the number of lives permitted before the game ends or whether the background soundtrack is on or off. Yet, even given the relatively modest changes to video games possible with the "GAME GENIE.TM.", the product has been extremely successful commercially.
Clearly, there are many applications that would be enabled if there were a means to make substantial modifications to video game cartridges in the field. Rather than simply slightly changing the attributes of existing characters in the game, entirely new characters could be introduced. Rather than just turning on or off the soundtrack, whole new soundtracks could be introduced. Modifications could also include temporary graphics or sounds that are briefly presented to the user in the form of an advertisement. In addition, peripheral devices such as modems or special game controllers, could be interfaced to the game such that the game could take advantage of them, even if the original authors of the game had no intention of supporting such peripherals.
Unfortunately, modifications such as those just described are far too extensive to be accomplished by a simple data word replacement device such as the "GAME GENIE.TM." (and other devices like Game Genie). Game Genie provides for the substitution of about a dozen bytes in the original cartridge. For new graphics and sound, thousands of new bytes of data are required, some replacing existing data in the cartridge, some in addition to existing data in the cartridge. Also, the "GAME GENIE.TM." architecture requires specific hardware to detect the memory address of each new word to be substituted on the cartridge. Given that many of the just described enhancements require thousands of new words to be substituted on the cartridge, it can easily be seen that it is impractical to simply extend the "GAME GENIE.TM." architecture to provide thousands of individual address comparators. Such a "multi-thousand-word" "GAME GENIE.TM." would be difficult to create at any cost, but would be certainly far too expensive for the home video game market.
Even if we provide a new video game enhancement device that, through some other means, can substitute or add thousands of words of data to an existing video game cartridge, we will quickly find that is impractical to distribute the new data in printed form (as it is today--in the form of codes--for "GAME GENIE.TM."). While it is reasonable for a person to have to enter tour codes in order to enhance a video game experience, it is not reasonable to have to enter 40 --or for that matter 40,000. Although the new data could be distributed in ROM or on floppy disks, the cost of the distribution media (if we include the cost of the readers for the distribution media), approaches or exceeds the cost of a new video game cartridge itself. The home video game market is targeted at children and young adults and is very cost sensitive. Clearly, a low-cost distribution means for new data would be required for a video game enhancement device to be successful.
Thus, a video game enhancement device that provides substantial enhancements is desirable, but technology existing in the art is not capable of substantial enhancements, and extensions of said existing technology to support substantial enhancements is far too expensive, both in terms of the actual hardware cost and the distribution costs for new data.
Another type of video game enhancement device has been recently announced, "THE EDGE.TM." by "P.F. MAGIC.TM.". Edge and P.F. Magic are trademarks of "P.F. MAGIC, INC..TM." This device provides communications capability to a "SEGA GENESIS.TM." video game console so as to allow two video games to communicate over a telephone line and play a video game or to allow a video game to connect to an on-line service (such as the "IMAGINATION NETWORK.TM.") so as to play on-line video games. "IMAGINATION NETWORK.TM." is a trademark of "IMAGINATION NETWORK INC..TM."
A principal limitation of the Edge is that it is not compatible with existing video game cartridges and it therefore requires completely new video games to be written specifically to take advantage of its communications capabilities to be of any value at all. Given that there are hundreds of existing video game cartridges on the market (none of which are compatible with "THE EDGE.TM."), and dozens in development that will not be compatible, there are clearly limitations to its usefulness.
Clearly, there would be significant advantage to a video game modem that was compatible with existing video game cartridges. Such a video game modem is not available in prior art systems.
An improved video game enhancer is described herein. It is capable of substantially enhancing existing video game cartridges, and it supports very low-cost distribution means that can conveniently deliver thousands of bytes of new data per game cartridge. One such low-cost distribution means is an integral modem which, by taking advantage of the improved enhancer capabilities, is compatible with existing video game cartridges and allows them to communicate over telephone lines.